During the last decade, CCS has been extended in different directions, among them priority and real time. One of the most satisfactory results for CCS is Milner’s complete proof system for observational congruence [?]. Observational congruence is fair in the sense that it is possible to escape divergence, reflected by an axiom recX.(τ.X + P ) = recX.τ.P . In this paper we discuss observational ...

The theory of chi processes with the mismatch operator is studied. Two open congruence relations are investigated. These are weak early open congruence and weak late open congruence. Complete systems are given for both congruence relations. These systems use some new tau laws. The results of this paper correct some popular mistakes in literature.

In the approximate fuzzy reasoning the covering over of fuzzy rule base input and rule premise of a rule determines the importance of that fuzzy rule and the rule output as well. An axiom system has been created, describing the relationship between the fuzzy rule base system, rule input and rule output. By using distance-based operators a novel reasoning method appears by the compositional rule...

We define an 2-fuzzy congruence, which is a weakened fuzzy congruence, find the 2-fuzzy congruence generated by the union of two 2-fuzzy congruences on a semigroup, and characterize the 2-fuzzy congruences generated by fuzzy relations on semigroups. We also show that the collection of all 2-fuzzy congruences on a semigroup is a complete lattice and that the collection of 2-fuzzy congruences und...

This paper is devoted to the discussion of the relationship between fuzzy rough set models and fuzzy topologies on a finite universe. The (TC) axiom for fuzzy topology is proposed. It is proved that the set of all lower approximation sets based on a reflexive and transitive fuzzy relation consists of a fuzzy topology which satisfies (TC) axiom; and conversely, a fuzzy topology which obey (TC) a...

We define a G-fuzzy congruence, which is a generalized fuzzy congruence, discuss some of its basic properties, and characterize the G-fuzzy congruence generated by a fuzzy relation on a semigroup. We also give certain lattice theoretic properties of Gfuzzy congruences on semigroups.

We redefine a fuzzy congruence, discuss some properties of the fuzzy congruences, find the fuzzy congruence generated by a fuzzy relation on a semigroup, and give some lattice theoretic properties of the fuzzy congruences on semigroups.

The paper investigates the non-symbolic algebraic semantics of the weak bisimulation congruenceson finite pi processes. The weak bisimulation congruences are studied both in the absence and inthe presence of the mismatch operator. Some interesting phenomena about the open congruences arerevealed. Several new tau laws are discovered and their relationship is discussed. The contributi...

Prefix iteration is a variation on the original binary version of the Kleene star operation P ∗Q, obtained by restricting the first argument to be an atomic action. Aceto and Ingólfsdóttir provided an axiom system for observation congruence over basic CCS with prefix iteration. However hitherto the only direct completeness proof given for such a system is very long and technical. In this paper,...

In this article, we provide the epistemicentrenchment characterization of the weak version of Parikh’s relevance-sensitive axiom for belief revision — known as axiom (P) — for the general case of incomplete theories. Loosely speaking, axiom (P) states that, if a belief set K can be divided into two disjoint compartments, and the new information φ relates only to the first compartment, then the ...